我有一个可以轻松公开的基本 JAXRS 服务，但有一次我希望使用依赖项注入(inject) API，我怀疑 Google Guice 将是最好的服务之一。考虑到这一点，我尝试集成它，但文档有点繁重，我不得不四处寻找以尝试找到正确的组合

• Web.xml
• 上下文监听器(我应该使用 ServletContainer 还是 GuiceContainer)
• 服务
• 是否使用@Singleton 或@Request 来注释服务，或者什么都不用(我应该使用@Singleton 进行注释——文档说我应该，但随后又说它默认为请求范围)
• 是否使用@InjectParam注解构造函数参数

但目前我从 Google Guice 收到错误，它们会根据我是否使用 @InjectParam 注释而改变。

如果我用@InjectParam 注释然后我得到

       Mar 29, 2013 9:52:04 PM com.sun.jersey.spi.inject.Errors processErrorMessages
   SEVERE: The following errors and warnings have been detected with resource and/or provider classes:
   SEVERE: The class com.hillingar.server.dao.interfaces.UserDao is an interface and cannot be instantiated.
   SEVERE: Missing dependency for constructor public com.hillingar.server.SessionUtility(com.hillingar.server.dao.interfaces.UserDao) at parameter index 0

如果我不注释然后我得到

    Mar 29, 2013 9:54:59 PM com.sun.jersey.spi.inject.Errors processErrorMessages
SEVERE: The following errors and warnings have been detected with resource and/or provider classes:
  SEVERE: Missing dependency for constructor public com.hillingar.server.rest.UserService(com.hillingar.server.dao.interfaces.UserDao,com.hillingar.server.SessionUtility) at parameter index 0
  SEVERE: Missing dependency for constructor public com.hillingar.server.rest.UserService(com.hillingar.server.dao.interfaces.UserDao,com.hillingar.server.SessionUtility) at parameter index 1

这是我的 web.xml

    <?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
    <filter>
        <filter-name>guiceFilter</filter-name>
        <filter-class>com.google.inject.servlet.GuiceFilter</filter-class>
    </filter>

    <filter-mapping>
        <filter-name>guiceFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

    <listener>
        <listener-class>com.hillingar.server.ServletContextListener</listener-class>
    </listener>

    <session-config>
        <session-timeout>
            30
        </session-timeout>
    </session-config>
</web-app>

这是我的 ServletContextListener

package com.hillingar.server;

import java.util.logging.Logger;

import javax.servlet.ServletContextEvent;

import com.google.inject.Guice;
import com.google.inject.Singleton;
import com.hillingar.server.dao.jdbcImpl.UserJdbc;
import com.hillingar.server.dao.interfaces.UserDao;
import com.sun.jersey.guice.JerseyServletModule;
import com.sun.jersey.guice.spi.container.servlet.GuiceContainer;
import com.sun.jersey.spi.container.servlet.ServletContainer;

public class ServletContextListener implements javax.servlet.ServletContextListener {

    Logger logger = Logger.getLogger(this.getClass().getName());

    @Override
    public void contextDestroyed(ServletContextEvent arg0) {
    }

        /*
         * Covered in URL
         * https://code.google.com/p/google-guice/wiki/ServletModule
         */
    @Override
    public void contextInitialized(ServletContextEvent arg0) {

            // Note the user of JerseyServletModule instead of ServletModule
            // otherwise the expected constructor injection doesn't happen
            // (just the default constructor is called)
            Guice.createInjector(new JerseyServletModule() {
                @Override
                protected void configureServlets() {

                    /*
                     * Note: Every servlet (or filter) is required to be a 
                     * @Singleton. If you cannot annotate the class directly, 
                     * you must bind it using bind(..).in(Singleton.class), 
                     * separate to the filter() or servlet() rules. 
                     * Mapping under any other scope is an error. This is to 
                     * maintain consistency with the Servlet specification. 
                     * Guice Servlet does not support the 
                     * deprecated SingleThreadModel.
                     */
                    bind(SecurityFilter.class).in(Singleton.class);
                    bind(ServletContainer.class).in(Singleton.class);

                    /*
                     * Filter Mapping
                     * 
                     * This will route every incoming request through MyFilter, 
                     * and then continue to any other matching filters before 
                     * finally being dispatched to a servlet for processing.
                     * 
                     */

                    // SECURITY - currently disabled
                    // filter("/*").through(SecurityFilter.class);

                    /*
                     * Registering Servlets
                     * 
                     * This registers a servlet (subclass of HttpServlet) called 
                     * ServletContainer, the same one that I would have used in 
                     * the web.xml file, to serve any web requests with the 
                     * path /rest/*  i.e. ...
                     * 
                        <servlet>
                            <servlet-name>ServletAdaptor</servlet-name>
                            <servlet-class>com.sun.jersey.spi.container.servlet.ServletContainer</servlet-class>
                            <load-on-startup>1</load-on-startup>
                        </servlet>
                        <servlet-mapping>
                            <servlet-name>ServletAdaptor</servlet-name>
                            <url-pattern>/rest/*</url-pattern>
                        </servlet-mapping>

                     */
                    serve("/rest/*").with(ServletContainer.class); // JAX-RS

                    // Using this and it starts bitching about
                    // com.sun.jersey.api.container.ContainerException: The ResourceConfig instance does not contain any root resource classes.
                    // So presumably wants an Application class that enumerates 
                    // all my services?
                    //serve("/rest/*").with(GuiceContainer.class);

                    /*
                     * Bindings
                     */
                    bind(UserDao.class).to(UserJdbc.class);
                    bind(SessionUtility.class);
                }
            });
    }

}

这是我的用户服务

package com.hillingar.server.rest;

import com.google.inject.Inject;
import com.google.inject.Singleton;
import java.util.List;

import javax.servlet.http.HttpServletRequest;
import javax.ws.rs.Consumes;
import javax.ws.rs.GET;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.SecurityContext;

import com.hillingar.server.SessionUtility;
import com.hillingar.server.dao.interfaces.UserDao;
import com.hillingar.server.model.User;
import com.hillingar.server.model.dto.AuthenticationResponse;

@Path("/user")
@Produces("application/json")
@Consumes({"application/xml","application/json"})
@Singleton // <-- Added Singleton here
public class UserService {

    private UserDao userDao;
    private SessionUtility sessionManager;

        /*
           Error if I annotate with @InjectParam...

           Mar 29, 2013 9:52:04 PM com.sun.jersey.spi.inject.Errors processErrorMessages
           SEVERE: The following errors and warnings have been detected with resource and/or provider classes:
           SEVERE: The class com.hillingar.server.dao.interfaces.UserDao is an interface and cannot be instantiated.
           SEVERE: Missing dependency for constructor public com.hillingar.server.SessionUtility(com.hillingar.server.dao.interfaces.UserDao) at parameter index 0

           Error If I don't annotate at all...
            Mar 29, 2013 9:54:59 PM com.sun.jersey.spi.inject.Errors processErrorMessages
            SEVERE: The following errors and warnings have been detected with resource and/or provider classes:
              SEVERE: Missing dependency for constructor public com.hillingar.server.rest.UserService(com.hillingar.server.dao.interfaces.UserDao,com.hillingar.server.SessionUtility) at parameter index 0
              SEVERE: Missing dependency for constructor public com.hillingar.server.rest.UserService(com.hillingar.server.dao.interfaces.UserDao,com.hillingar.server.SessionUtility) at parameter index 1

           (both output Initiating Jersey application, version 'Jersey: 1.13 06/29/2012 05:14 PM')
        */
    @Inject
    public UserService(UserDao userDao, SessionUtility sessionManager) {
        this.userDao = userDao;
                this.sessionManager = sessionManager;
    }

    @GET
    public List<User> test(@Context HttpServletRequest hsr) {
                // USER DAO IS ALWAYS NULL - CONSTRUCTOR INJECTION NOT WORKING
        User loggedInUser = userDao.findBySessionId(hsr.getSession().getId());
                ...
        return users;
    }

}

最佳答案

将 ServletContextListener 更改为

package com.hillingar.server;

import java.util.logging.Logger;

import javax.servlet.ServletContextEvent;

import com.google.inject.Guice;
import com.google.inject.Injector;
import com.google.inject.Singleton;
import com.google.inject.servlet.GuiceServletContextListener;
import com.hillingar.server.dao.jdbcImpl.UserJdbc;
import com.hillingar.server.dao.interfaces.UserDao;
import com.hillingar.server.rest.UserService;
import com.sun.jersey.guice.JerseyServletModule;
import com.sun.jersey.guice.spi.container.servlet.GuiceContainer;
import com.sun.jersey.spi.container.servlet.ServletContainer;

// (1) Extend GuiceServletContextListener
public class ServletContextListener extends GuiceServletContextListener {

    Logger logger = Logger.getLogger(this.getClass().getName());

    // (1) Override getInjector
    @Override
    protected Injector getInjector() {
        return Guice.createInjector(new JerseyServletModule() {
            @Override
            protected void configureServlets() {
                bind(SecurityFilter.class).in(Singleton.class);
                bind(UserService.class);// .in(Singleton.class);
                bind(ServletContainer.class).in(Singleton.class);

                // (2) Change to using the GuiceContainer
                serve("/rest/*").with(GuiceContainer.class); // <<<<---

                bind(UserDao.class).to(UserJdbc.class);
                bind(SessionUtility.class);
            }
        });
    }
}

关于java - 如何让 Google Guice 与 JaxRS( Jersey )一起工作，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/15712233/